Oficina Regional de la FAO para América Latina y el Caribe |

IRRIGATION IN ANTIGUA & BARBUDA

Climate

Antigua enjoys a semi-arid, tropical climate with an average annual rainfall range of 1 070 - 1 140 mm, unevenly distributed with peaks during the months of October to December and extended periods of drought during March to June. Barbuda is drier with average annual rainfall ranging between 760 - 990 mm.
Droughts occur every five to ten years. When several low-rainfall years occur consecutively, the country faces critical water shortages. In 1983-84 water had to be imported from other countries.

Water Resources

The total average rainfall for both islands is estimated at 453 million m3/year and IRWR about 52 million m3/year. There are no perennial water sources in the country. At present the country's agricultural and municipal (domestic and commercial) water demands are being met by two desalination plants (total capacity 3.3 million m3/year); three surface dams, numerous small ponds and 5 well fields (total capacity 2.8 millions of m3/year). Individual residences have cisterns which provide part or all of the household water needs. The amount of water collected through this method is not known.
Water for Barbuda is supplied from a single well that serves Codrington where most of the population lives. The groundwaters are generally saline with the notable exception of Palmetto Sands, a 600 ha area of beach sands on the southwestern shore.

Lakes and dams

Total dam capacity in Antigua was about 7 million m3 in 1992. It is estimated that there are over 500 ponds, each with capacity less than 1 000 m3. The small ponds are used primarily for agriculture and many of the reservoirs are used for both agricultural and municipal uses. During drier months irrigation is restricted to a very limited surface due to shortfall in surface and groundwater yields, and most surface water storage is diverted to municipal supply. On the other hand, Barbuda's topography and geology are not well suited to dam construction.

Water withdrawal

Annual water withdrawal in 1990 was about 5 million m3, of which the domestic sector accounts for 60%, while agriculture and industry account for 20% each.
The entire population, both rural and urban, has access to potable water. Most of the municipal water is treated at three main treatment plants.

Irrigation and drainage development

Owing to the low annual rainfall and high evapotranspiration, irrigation is a necessity for the successful cultivation of crops. Irrigation potential has been estimated at 319 ha. This estimate is based on developing surface water storage capacity in an economically rational manner. Proposed sites with favourable development potential have been selected on the basis of their topographic suitability, geological conditions and proximity to agricultural lands.
Approximately 7% (130 ha) of cultivated land is currently irrigated in Antigua and Barbuda. Sprinkler and micro-irrigation systems are mainly used on 19.0 and 78.6% of the irrigated area, respectively. The remaining 2.4% are equipped inland valley bottom land.

Surface supplies are the main source of irrigation water for agriculture, with occasional use of groundwater when municipal demands allow. Agriculture uses about 21% of the municipal water supplied, as priority is given to domestic and municipal uses. Many small dams have not been used efficiently and underutilization and lack of maintenance have resulted in the deterioration of these facilities.
An assessment of the natural resources of Antigua and Barbuda identified reclamation and recycling of treated sewage as a potential source of agricultural water supply. The report estimated that up to 4 550 m3/day could be collected from some 600 ha of urban area if adequate sewage system existed. Villages, hotels and the airport were also identified as potential sources of reclaimable waste suitable for tree crops and pasture irrigation. It was assessed that as much as 80% of non-agricultural water demands could be reclaimed for limited agricultural uses.
There are three main government-owned irrigation schemes in Antigua - the Sanderson, Bethesda and Potworks Irrigation Projects. The Sanderson Project is the smallest with a size of 8 ha. It is a micro-irrigation system which supplies 10 households. The second largest project is at Bethesda, a sprinkler irrigation system serving 10 households. The Potworks Project is the largest, extending some 50 ha, serving 15 households. Both sprinkler and micro-irrigation systems are used in this project. All three irrigation projects service farms which are 1 ha or less in size. There is no charge for the use of irrigation water obtained from surface dams or ponds. Where irrigation water is obtained from the municipal water supply, the user is charged.
About 120 ha of annual and 10 ha of permanent crops are irrigated. Primarily, vegetables such as tomatoes, onions, cucumbers, water melon and cabbage are irrigated.
The drained surface area is about 808 ha and is limited to on-farm drains constructed to dispose of excess rainfall and downhill runoff.

Trends in water resources management

Freshwater is a scarce resource in Antigua and Barbuda. In the context of a growing tourist industry, demand for water is rising. The Antigua Public Utilities Authority has a long-term water development plan with emphasis on desalinization of seawater to eliminate the risk of drought and inadequate surface storage and groundwater facilities.
Currently there is no irrigation and agricultural water development policy in Antigua and Barbuda. Adhoc programmes and projects are generally used to satisfy the individual farmer's demand for small-scale irrigation infrastructure, such as small dams. An agricultural water resource development committee has been proposed in a recent seminar to formulate appropriate policy and projects to develop irrigation in Antigua and Barbuda.
CARDI has been promoting a dryland farming system among smallholder farmers by demonstrating drip irrigation, water harvesting, mulching, minimum tillage and drought tolerant crops for sustainable agricultural production in the Eastern Caribbean islands.